Posted by David Fix (209.77.208.34) on October 09, 2000 at 11:26:06:
The bird on the left leaves me stumped. Unlike one or two other respondents I can see no undertail pattern, just a hint of blurry paleness in a couple of spots, which is not helpful. I don't think this is anything more than a 'can you take a stab at this?' type of quiz and as such it doesn't seem it's going to do much to educate us. Were this bird to turn right or left the mystery would likely dissolve instantly. The bird on the right has to be a MacGillivray's Warbler. The prominent clubby eye-arcs, especially the bottom one, eliminate Orange-crowned, as does the visibly pale lower mandible which no Orange-crowned beyond an early juvenile ought to show (this is a pers. sugg., not a fact). The smeary dark sides of the breast pinching off a dingy off-whitish chin and throat, as well as the sooty lores, also point to this species. Even the inquisitive upright 'spished-in' posture looks like that of a Mac. The vague side streaks might seem troublesome---are they real?---but the whole bird looks like a Mac and not like one of those Orange-crowns lately nicknamed by an Oregon birder 'the warbler from heck'.